It looks like we have different sets here - from the question guaranteed at least two BOTH and NONE. I also suspect two more sets which are Computer skills (CS) and Writing skills(WS). CS&WS=20%, find NONE-?

st(1) CS=2*WS. From question stem we can deduce 40% required CS, also at least 20% required WS, BUT we don't know how much exactly WS were required. Not Sufficient;

st(2) WS=45%, we can deduce that at 45% required Only WS and 20% required CS&WS. Hence total 65% required WS and at least 20% required CS, BUT we don't know for sure how many surveyed companies required CS. Not Sufficient;

Combined st(1&2) should be sufficient, as know that 20% required CS Only and 45 required WS Only PLus 20 required BOTH CS&WS. Hence 100 -(45+20+20) =15 % did not require any skills NONE

IOM C

yvonne0923 wrote:Of the companies surveyed about the skills they required in prospective employees, 20% required both computer skills and writing skill. What percent of the companies surveyed required neither computer skills nor writing skills?

(1) Of those companies surveyed that required computer skills, half required writing skills.
(2) 45% of the companies surveyed required writing skills but not computer skills.

yvonne0923 wrote:Of the companies surveyed about the skills they required in prospective employees, 20% required both computer skills and writing skill. What percent of the companies surveyed required neither computer skills nor writing skills?

(1) Of those companies surveyed that required computer skills, half required writing skills.
(2) 45% of the companies surveyed required writing skills but not computer skills.

Use a Venn Diagram. Given information:



Statement 1: Of those companies surveyed that required computer skills, half required writing skills.
In other words, half the computer circle is in the overlap -- which represents the companies that required both computer and writing skills -- so half the computer circle is not in the overlap:



No way to determine how many companies required only writing skills.
Insufficient.

Statement 2: 45% of the companies surveyed required writing skills but not computer skills.



No way to determine how many companies required only computer skills.
Insufficient.

Statements 1 and 2 together:



20+20+45 = 85% of the companies required computer skills only, writing skills only, or both.
Thus, 100-85 = 15% required neither.
Sufficient.

The correct answer is C.